I am a 24 year old male, who lives in Minnesota, and would like my 16 year old sister, who lives in New York, to move in with me and my family, because at the time she is living with our grandparents( they currently have custody of her) and they are becoming much to elderly to take care of her and are not helping her in school( her grades are terrible). Her father(not my father) has joint custody of her, and she visits him on the weekends, and OUR mother has passed away. I just need to know what is needed to make this happen as soon as possible.Do our grandparents just need to agree and it's just paper signing from there, or is it going to be a whole big court thing? Thank you.

I don't know what you mean by the father has joint custody.

I'm actually in NY, familiar with the system. Is there a Court Order in place concerning custody? What does it say (briefly)? In general you would have to bring an action in NY to assume custody of her. Her father would "probably" need to agree OR you would have to make a very strong, if not overwhelming argument, concerning what is best for her.

Undoubtedly the Grandparents would agree if they are stressed. The father? I don't know.

His argument could be that he visits her X hours a week and if she moves away he will lose that time with her. That can be overcome, of course, by fewer but larger blocks of hours.

A side note (totally inappropriate here) - there should be more siblings like you.

If the father of the child is involved and is getting regular visitation then you will have to seek his permission before any kind of a move could take place.